The present invention relates to a method for checking and/or calibrating a horizontal axis of a rotating laser.
Rotating lasers are used indoors and outdoors for leveling and marking tasks, such as displaying laser markings running horizontally, vertically, or diagonally on a target surface, or determining and checking horizontal heights, perpendicular lines, alignments, and plumb points. Rotating lasers can be arranged in various device positions, which are designed as horizontal positions and vertical positions. A distinction is thereby made between horizontally usable rotating lasers, which are solely used in the horizontal position, and horizontally and vertically usable rotating lasers, which are used in the horizontal position and the vertical position. Horizontally usable rotating lasers have as device axes a first horizontal axis and a second horizontal axis, which run perpendicular to each other and span a horizontal plane. Horizontally and vertically usable rotating lasers have as a device axis, in addition to the first and second horizontal axes, a vertical axis that runs perpendicular to the horizontal plane of the first and second horizontal axes.
To ensure the accuracy of a rotating laser when in operation, the accuracy must be checked regularly and if a maximum difference defined by the device manufacturer is exceeded, the rotating laser must be calibrated. The accuracy of the rotating laser is thereby checked for every device axis. Methods are known for checking and/or calibrating a horizontal axis and for checking and/or calibrating a vertical axis. For horizontally usable rotating lasers, the first and second horizontal axes are checked sequentially, wherein the sequence is arbitrary. For horizontally and vertically usable rotating lasers, after the first and second horizontal axes are checked, a check of the vertical axis is performed.
The orientation of the device axes in a defined state occurs by means of a leveling device of the rotating laser. The defined state of the rotating laser in the horizontal position is referred to as the horizontal state and in the vertical position as the vertical state. The leveling device comprises a first leveling unit that orients the first horizontal axis in a first defined state, a second leveling unit that orients the second horizontal axis in a second defined state, and for a vertically usable rotating laser, there is a third leveling unit that orients the vertical axis in a third defined state. Each of the leveling units comprises an inclination sensor that measures the inclination of the device axis, and an adjustment element with which the inclination of the device axis can be adjusted. Ideally, the inclination sensors are oriented parallel to the allocated device axes. If an inclination sensor is not parallel to the allocated device axis, the device axis will have an inclination error.
In the operating instructions of their rotating lasers, the device manufacturers of horizontally and vertically usable rotating lasers define methods for checking the first and second horizontal axes, which are to be performed regularly by the operator, and methods for calibrating the vertical axis, which are to be performed regularly by the operator, if the established maximum difference for the horizontal axis is exceeded. The known methods for checking and/or calibrating a horizontal axis are based on the principle of an envelope measurement. The rotating lasers are set up in the horizontal position on a stable substrate or on a tripod at a measurement distance to a measuring surface and the horizontal axes of the rotating laser are oriented in a horizontal state. Every device manufacturer defines the measurement distance between the rotating laser and the measuring surface and establishes a maximum difference for the horizontal axes.
In the known methods for checking the horizontal axes, the rotating laser is oriented in a first angular position in which the horizontal axis to be checked is pointed toward the measurement surface and the position in which the laser beam strikes the measurement surface is marked as a first control point. The rotating laser is rotated by 180° around the axis of rotation into a second angular position in which the horizontal axis to be checked is pointed opposite to the first angular position on the measurement surface, and the position in which the laser beam strikes the measurement surface is marked as the second control point. The distance between the first and second control points on the measurement surface is determined as the difference and compared with the maximum difference for the horizontal axes specified by the unit manufacturer. If the difference is greater than the maximum difference, a calibration of the checked horizontal axis or a calibration of all the unit axes of the rotational laser is necessary.
The known methods for the calibration of a horizontal axis are carried out after the checking of the horizontal axes, if the difference between the first and second control points on the measurement surface is greater than the maximum difference. If the position and orientation of the rotating laser did not change, the calibration of the horizontal axis by means of the first and second control points on the measurement surface can be performed. The rotating laser is adjusted by means of the leveling device until the laser plane is located in the middle between the first and second control points. This position of the laser plane is stored as the new zero position for the horizontal axis. If the position and/or the orientation of the rotating laser has changed, the steps of the method for the checking of the horizontal axis must be repeated and the positions where the laser beam strikes the measurement surface must be marked as new control points.
On the LAR-250 rotating laser manufactured by Stabila, the first and second horizontal axes are checked in a joint method for inclination errors. The LAR-250 rotating laser is set up at a measurement distance of 5 m or 10 m from the measurement surface. The rotating laser is oriented in four angular positions one after another that differ from one another by 90°, and the positions where the laser beam strikes the measurement surface are marked as control points on the measurement surface. In the first angular position, the first horizontal axis is oriented on the measurement surface and the laser beam produces a first control point. In the second angular position, the second horizontal axis is oriented on the measurement surface and the laser beam produces a second control point. In the third angular position, the first horizontal axis is oriented opposite to the first angular position on the measurement surface and the laser beam produces the third control point. In the fourth angular position, the second horizontal axis is oriented opposite to the second angular position on the measurement surface and the laser beam produces a fourth control point. The distance between the first and third control points is defined as the first difference and the distance between the second and fourth control point is defined as the second difference. If the first and/or second difference is greater than the maximum difference, the operating instructions specify a calibration of the first and second horizontal axis. The maximum difference is 1 mm at a measurement distance of 5 m, and 2 mm at a measurement distance of 10 m. The calibration of the first horizontal axis is done by means of the first and third control points and the calibration of the second horizontal axis is done by means of the second and fourth control points. The laser plane that is spanned by the rotating laser beam is adjusted by means of the first leveling unit until the laser plane is located in the center between the first and third control points, and by means of the second leveling unit, until the laser plane is located in the center between the second and fourth control points. These positions of the laser plane are stored as new zero positions for the first and second horizontal axes. The center position between the first and third control points corresponds to a new first zero position for the first horizontal axis and the center position between the second and fourth control point corresponds to a new second zero position for the second horizontal axis.
On the Sokkia TRIAX UL-300 the first and second horizontal axes are checked as described above in separate test methods for inclination errors. The rotating laser is set up at a measurement distance of 15 m or 30 m from a measurement surface. In a first test method, the first horizontal axis is checked for a first inclination error and optionally is calibrated in a first calibration method. In a second calibration method, the second horizontal axis is checked for a second inclination error and optionally calibrated in a second calibration method. After the separate verification and calibration methods for the first horizontal axis and the second horizontal axis have been performed, the first and second horizontal axes are compared in a final check of the horizontal axes. For this purpose, the two control points of the first test method for the first horizontal axis and the two control points of the second test process for the second horizontal axis are compared with each other and a maximum distance between the four control points is determined. The maximum separation between the control points is compared with a maximum difference. The maximum difference is 3 mm at a measurement distance of 15 m and 6 mm at a measurement distance of 30 m. When the maximum separation is not greater than the maximum difference, the first and second horizontal axes are within the specified tolerance. The operating instructions for the UL300 do not say what the user has to do if the maximum distance between the four control points is greater than the maximum difference.
On the GR L 500 HV rotating laser manufactured by Bosch Power Tools, the method for the calibration of the horizontal axes differs from the sequence described above in that the control points marked on the measurement surface in the checking process are not referenced for the calibration. The rotating laser is set up at a measurement distance of 30 m from the measurement surface. The first and second horizontal axes are checked for inclination errors as described above by comparing the distance between the two control points with the maximum difference. Bosch Power Tools has specified a maximum difference of 6 mm for the horizontal axes. The method for the calibration of the horizontal axis includes the following steps: the rotating laser is oriented in a first angular position in which the horizontal axis to be calibrated is oriented on the measurement surface. The position in which the laser beam strikes the surface is transferred by means of a laser receiver as a first centerline to the measurement surface. The rotating laser is rotated by 180° into a second angular position in which the horizontal axis to be calibrated is oriented in an opposite axial direction on the measurement surface. The position in which the laser beam strikes the measurement surface is transferred by means of the laser receiver as a second centerline to the measurement surface. The center position between the first centerline and the second centerline is determined by means of the laser receiver. The rotating laser beam is adjusted by means of the leveling device of the rotating laser until the laser beam is located on the center position between the first and second centerlines. The inclination of the laser beam can be adjusted by means of a laser receiver. For this purpose, the center marking of the laser receiver is located above the center position between the first and second centerlines and the inclination of the laser beam is adjusted in the direction of the horizontal axis until the laser plane is located on the center marking of the laser receiver.
The known methods for the checking and/or calibration of a horizontal axis of a rotating laser have the disadvantage that the positions in which the laser beam strike the measurement surface must be manually transferred by the user to the measurement surface and are not suitable for an automated performance of the method. The accuracy of the method it is also a function of the care taken by the user in the determination of the center point of the laser beam, the transfer of the center point to the measurement surface and the determination of the distance between the control points. An additional disadvantage is that the measurement distance between the rotating laser and the measurement surface is specified in a fixed manner for the performance of the method. The measurement distance of 30 m specified for the GRL 500 HV rotating laser manufactured by Bosch Power Tools it is frequently not available for measurement tasks indoors.
EP 2 781 880 A1 describes a method for checking a horizontal plane of a rotating laser and a method for the calibration of the horizontal plane of the rotating laser. The method differs from the sequences described above in that the checking of the horizontal plane of the rotating laser it is not done by checking the first and second horizontal axes but is done in three or any arbitrary number more than three angular positions. For the angular positions of the rotating laser, arbitrary orientations can be selected. The selected angular positions are co-determined on the basis of a direction determination functionality in the framework of the respective method steps. In the method for the checking of the horizontal plane, the rotating laser is manually oriented by the user or automatically by means of a motorized rotating platform into the at least three angular positions and the respective position in which the leveled laser beam strikes a detection field of a laser receiver is stored. EP 2 781 880 A1 does not provide any information how the calibration of the horizontal plane of the rotating laser is done. All it says is that if the requirements are not met or are not fully satisfied, the calibration data stored for the beam horizontal functionality will be automatically updated by the control and evaluation device.
The object of the present invention consists of developing a method for checking and/or calibrating a horizontal axis of a rotating laser with a high degree of accuracy. In addition, the method is to be adaptable to the respective ambient conditions of the measurement environment and be suitable for automated execution.
According to the invention, the method for checking and/or calibrating a first or second horizontal axis of a rotating laser, which projects a first laser beam that is rotatable about an axis of rotation, comprises the following steps:                The rotating laser is positioned at a measurement distance DH from a laser receiver, wherein the rotating laser is oriented in the horizontal position and the laser receiver is oriented in a longitudinal arrangement,        The first and second horizontal axes of the rotating laser are oriented in a horizontal state, wherein the horizontal state is established by a first zero position and the second horizontal axis is established by a second zero position,        The rotating laser is arranged in a first angular position, wherein the horizontal axis to be checked is oriented in the first angular position on a detection field of the laser receiver,        The incident position of the laser beam on the detection field of the laser receiver is defined as a first control point and the distance of the first control point from a zero position of the detection field is stored as the first height offset H1,        The rotating laser is arranged in a second angular position, wherein the second angular position is rotated by 180° to the first angular position about the axis of rotation of the rotating laser.        The incident position of the laser beam on the detection field of the laser receiver is defined as the second control point and the distance of the second control point from the zero position of the detection field is stored as a second height offset H2,        The distance between the first control point and the second control point is calculated as difference Δ from the first and second height offsets,        The measurement distance DH between the rotating laser and the laser receiver is determined, and        The difference Δ is compared against a maximum difference Δmax.        
In regard to the method according to the invention for checking and/or calibrating a horizontal axis, the measurement distance between the rotating laser and the laser receiver is measured and is not set to a predetermined measurement distance. This has the advantage that the measurement distance can be adapted to the ambient conditions of the measurement environment. In the method according to the invention, the method step in which the measurement distance is determined between the rotating laser and the laser receiver, can be executed at various locations. In the method according to the invention, the incident positions of the laser beam are determined using a laser receiver and stored as height offsets from the zero position of the detection field. By using a laser receiver with a measurement function, the measurement accuracy is increased in executing the method. The laser receiver determines the incident position of the laser beam on the detection field according to a fixed routine.
This has the advantage that the accuracy of the method is independent of the care taken by the operator and is suitable for the automated execution of the method. When the rotating laser is located on a motorized rotating platform, the method according to the invention can be conducted in a fully automated manner In a semi-automatic design, the operator manually places the rotating laser in the first and second angular positions on request; all other method steps are carried out by the rotating laser and laser receiver.
Preferably, the measurement distance between the rotating laser and the laser receiver is determined by means of the rotating laser beam and the laser receiver. The method according to the invention has the advantage that the ambient conditions of the measurement environment can be taken into account when checking and/or calibrating the horizontal axis, and that furthermore no additional device components are required. The measurement distance between the rotating laser and the laser receiver is selected as permitted by the measurement environment.
In a particularly preferred manner, the measurement distance between the rotating laser and the laser receiver is determined as a first distance by means of a first measuring procedure, as a second distance by means of a second measuring procedure, or as a distance averaged from the first and second distances. If the measurement distance between the rotating laser and the laser receiver can be determined by means of various measuring procedures, the method for checking and/or calibrating a horizontal axis can be adapted to the ambient conditions of the measurement environment and the functions of the measuring devices (rotating laser and laser receiver).
In a first preferred embodiment, the measurement distance between the rotating laser and the laser receiver is determined as a first distance by means of the first measuring method. In the first measuring method, the laser beam is inclined by an inclination angle and the distance of the inclined laser beam from the zero position of the detection field is stored. The first measuring method is suited for laser receivers with a measuring function which can measure the distance of a laser beam from a zero position as a height offset. In the method according to the invention, the measurement of the first distance may occur in the first angular position or the second angular position. The inclination of the laser beam by the inclination angle may be accomplished by means of the leveling device of the rotating laser. The leveling device comprises a first leveling unit that orients the first horizontal axis in a first defined state [and] a second leveling unit that orients the second horizontal axis in a second defined state. If the first horizontal axis is checked or calibrated, the first horizontal axis is oriented on the detection field of the laser receiver and the laser beam is inclined by means of the first leveling unit about the second horizontal axis, whereby the adjustment of the angle of inclination is accomplished by means of a first adjustment element and a first inclination sensor of the first leveling unit. When the second horizontal axis is checked or calibrated, the second horizontal axis is oriented on the detection field of the laser receiver and the laser beam is inclined by means of the second leveling unit about the first horizontal axis, wherein the adjustment of the inclination angle occurs by means of a second adjusting element and a second inclination sensor of the second leveling unit.
In a first variant of the first measuring procedure, the rotating laser is oriented horizontally, the horizontally oriented laser beam is set to the zero position of the detection field, the laser beam is inclined toward the laser receiver by an inclination angle α, the incident position of the inclined laser beam on the detection field of the laser receiver is determined as a first measuring point, the distance of the first measuring point from the zero position of the detection field is stored as first height h1=h(α) and the first distance d1 is calculated from the inclination angle α and a height difference Δh between the first height h1 and the zero position of the detection field. When the longitudinal direction of the laser receiver is oriented parallel to the direction of gravity, the first distance d1 can be calculated according to the formula tan(α)=Δh/d1. For small inclination angles α, tan(α)≈sin(α) approximately. The first variant of the first measuring procedure is particularly suited for rotating lasers and laser receivers with an auto-alignment function, in which the height adjustment of the laser beam to the zero position of the detection field of the laser receiver can be performed automatically.
In a second variant of the first measuring procedure, the rotating laser is oriented horizontally, the incident position of the horizontally oriented laser beam on the detection field of the laser receiver is determined as a reference point, the distance of the reference point from the zero position of the detection field is stored as reference height h0=h(0°), the laser beam is inclined by inclination angle α, the incident position of the inclined laser beam on the detection field is determined as a first measuring point, the distance of the first measuring point from the zero position of the detection field is stored as first height h1=h(α) and the first distance d1 is calculated from the inclination angle α and a height difference Δh between the first height and the reference height. When the longitudinal direction of the laser receiver is oriented parallel to the direction of gravity, the first distance d1 can be calculated according to the formula tan(α)=(h1−h0)/d1=Δh/d1. For small inclination angles α, tan(α)≈sin(α) approximately. The second variant of the first measuring procedure is suited for rotating lasers and laser receivers without an auto-alignment function. The operator must only ensure that the laser beam inclined at inclination angle α is captured by the detection field of the laser receiver. For a rotating laser and laser receiver with an auto-alignment function, the laser beam is automatically moved into the area of the detection field.
In a third variant of the first measuring procedure, the rotating laser is oriented horizontally, the horizontally oriented laser beam is inclined in an inclination direction by inclination angle α, the incident position of the inclined laser beam on the detection field of the laser receiver is determined as the first measuring point, the distance of the first measuring point to the zero position of the detection field is stored as first height h1=h(α), the laser beam is inclined in an opposing inclination direction by a negative inclination angle −α, the incident position of the inclined laser beam on the detection field is determined as the second measuring point, the distance of the second measuring point from the zero position of the detection field is stored as second height h2=h(−α) and the first distance d1 is calculated from the inclination angle α and a height difference Δh between the first height and the second height. When the longitudinal direction of the laser receiver is oriented parallel to the direction of gravity, the first distance d1 can be calculated according to the formula tan(2α)=(h(α)−h(−α))/d1=Δh/d1. For small inclination angles α, tan(2 α)≈sin(2 α) approximately. The third variant of the first measuring procedure is suitable for rotating lasers and laser receivers with and without an auto-alignment function. When the laser beam is initially oriented to the zero position of the detection field or at least in the vicinity of the zero position, the entire detection height of the detection field can be used. For a device system with an auto-alignment function, the adjustment to the zero position can be performed automatically.
In a second preferred embodiment, the measurement distance between the rotation laser and the laser receiver is determined as the second distance by means of the second measuring procedure. In the second measuring procedure, the rotating laser is oriented horizontally, the laser beam is moved at a known speed vR around the axis of rotation, the signal length ts of the laser beam on the detection field of the laser receiver is determined and the second distance d2 is calculated from the speed of rotation vR, signal length ts and detection width BD of the detection field. When the longitudinal direction of the laser receiver is oriented parallel to the direction of gravity, the second distance d2 can be calculated according to the formula ts/tfull=BD/(2πd2), where tfull=60/vR. The speed of rotation vR is indicated in revolutions per minute and time tfull required for one revolution is 60/vR. The second measuring procedure is suitable for rotation lasers and laser receivers without an auto-alignment function. The laser receiver must be able to measure signal length ts of the laser beam on the detection field.
In a third preferred embodiment, the measurement distance between the rotating laser and the laser receiver is determined as the distance averaged from the first and second distances. By averaging the first and second distances, the accuracy with which the measurement distance between the rotating laser and the laser receiver can be determined can be increased. The first distance, which is determined using the first measuring procedure, is greater than or equal to the actual measurement distance. When the transverse direction of the laser receiver is not oriented parallel to the direction of gravity but is inclined in relation to the direction of gravity, the horizontal distance perpendicular to the direction of gravity is less than the distance the detection field of the laser receiver measured. The second distance, which is determined using the second measuring procedure, is less than or equal to the actual measurement distance. When the longitudinal direction of the laser receiver is not oriented parallel to the direction of gravity but is inclined in relation to the direction of gravity, the horizontal distance in the direction of gravity the laser beam passes over on the detection field, is greater than detection width BD of the detection field.
In a preferred development of the method, an inclination of the laser receiver relative to a direction of gravity is determined as a first vertical angle φ1 in a first vertical plane and/or as a second vertical angle φ2 in a second vertical plane, wherein the first vertical plane is spanned by the direction of gravity and a perpendicular vector of the detection field of the laser receiver and the second vertical plane is spanned by a longitudinal direction and a transverse direction of the detection field. The first vertical angle φ1 is measured between the perpendicular vector of the detection field and the direction of gravity, wherein the first vertical angle φ1 represents the deviation of 90° between the perpendicular vector and the direction of gravity, and the second vertical angle φ2 is measured between the direction of gravity and the longitudinal direction of the detection field. In executing the method according to the invention, the laser receiver is oriented in a longitudinal arrangement, wherein the longitudinal direction of the detection field should run perpendicular to the direction of gravity and the transverse direction of the detection field should run parallel to the direction of gravity. By inclining the laser receiver relative to the direction of gravity, the horizontal and vertical distances deviate from the distances that the detection field of the laser receiver measured. If the inclination of the laser receiver is known, the dimensions can be corrected accordingly. The laser receiver may be inclined relative to the direction of gravity by the first and/or second vertical angle. The inclination of the laser receiver can be measured by means of a 2-axis acceleration sensor or by means of two 1-axis acceleration sensors.
In a particularly preferred manner, in the evaluation with the laser receiver for the first vertical angle φ1 and/or the second vertical angle φ2, an angle-dependent correction factor cos(φ1), cos(φ2), 1/cos(φ2) is multiplied. By the multiplication with an angle-dependent correction factor or with a plurality of angle-dependent correction factors, the inclination of the laser receiver can be compensated by the first vertical angle φ1 and/or the second vertical angle φ2. In the formulas that use the measuring function of the laser receiver and measure distances on the detection field in the longitudinal direction, the distances are multiplied by a correction factor cos(φ1) for the first vertical angle φ1 and a correction factor cos(φ2) for the second vertical angle φ2. The correction factor cos(φ1)·cos(φ2) is to be taken into account in the distance measurement of the measurement distance using the first measuring procedure, in determining the difference between the first and second control points, and calculating the correction angle within the scope of the method according to the invention. In regard to the distance measurement of measurement distance DH as the second distance using the second measuring procedure, the conventional measuring function of the laser receiver in the longitudinal direction is not used, but the detection width in the transverse direction. By inclining the laser receiver in the second vertical plane by second vertical angle φ2, the horizontal distance that the laser beam passes over in the detection field is greater than the detection width BD of the detection field. The signal length of the rotating laser beam corresponds to the horizontal distance on the detection field. For the horizontal distance, the correlation BD/cos(φ2) applies. An inclination of the laser receiver by the first vertical angle φ1 does not change the horizontal distance. The angle-dependent correction factor 1/cos(φ2) is taken into account in the distance measurement using the second measuring procedure.
In a preferred development of the method, for orienting the horizontal to be checked in the horizontal state, a plurality of zero positions are recorded as a function of a temperature or a temperature-dependent measured value and stored in a characteristic curve. The term “characteristic curve” thereby comprises both a continuous characteristic curve as well as a table with discrete value pairs of zero positions and temperatures, or of zero positions and temperature-dependent measured values. The stored characteristic curve represents for the horizontal axis of the rotating laser to be checked a correlation between the temperature and the temperature-dependent measured value and the zero position of the inclination sensor. The inclination angle that corresponds to the defined state of the horizontal axis is defined as the zero position. From the characteristic curve, a zero position can be read for every temperature from the approved operating temperature range.
Preferably, the temperature or the temperature-dependent measured variable of the rotating laser is measured, the zero position associated with the temperature or measured value is determined from the characteristic curve, and the horizontal axis is oriented in the state defined by the zero position. By means of the temperature measurement, it is possible to increase the device accuracy of the rotating laser, since the influence of the temperature on the device accuracy of the rotating laser is reduced.
In a particularly preferred manner, the temperature of the rotating laser is measured by means of an inclination sensor, which comprises a housing that is filled with a liquid and a gas bubble, a light source and at least one photo detector. The measurement of the temperature of the rotating laser by means of the inclination sensor of the leveling unit has the advantage that the temperature is measured exactly at the location in the device housing of the rotating laser that is relevant for orienting the horizontal axis. In addition, no additional sensor element is required for temperature measurement, so that the equipment cost for the temperature measurement is reduced.
In a particularly preferred manner, an additional characteristic curve of temperatures and bubble lengths of the gas bubble is stored, the bubble length of the gas bubble is measured using the light source and the photo detector of the inclination sensor, and the temperature associated with the measured bubble length is determined using the additional characteristic curve. The gas bubble of the inclination sensor has a bubble length that is temperature-dependent and is thus suitable as a measured variable for the temperature. The bubble length can be measured using the light source and the photo detector of the inclination sensor. For the temperature measurement, no additional sensor element is required; the temperature is measured solely using the components of the inclination sensor.
In a preferred manner, a correction angle θ is calculated from the measurement distance DH, the first height offset H1 and the second height offset H2, and the correction angle θ is stored as the new zero position for orienting the horizontal axis in the horizontal state when the difference Δ is greater than the maximum difference Δmax. The measurement distance DH between the rotating laser and the laser receiver was determined as a first distance, as a second distance or as an averaged distance, and is required for calibrating the horizontal axis. If the difference Δ between the first and second control points is greater than the maximum difference Δmax defined by the device manufacturer, the rotating laser does not meet the indicated device accuracy and the horizontal axis must be calibrated. The correction angle θ may be calculated according to the formula tan(θ)=(H1−H2)/2DH.
In a particularly preferred manner, the calibrated horizontal axis is checked in an additional check loop, wherein the horizontal state of the horizontal axis is defined by the new zero position. The device axes are oriented in the horizontal state and the method for checking the horizontal axis is carried out. The distance between the first control point, which is determined in the first angular position, and the second control point, which is determined in the second angular position, is calculated as difference Δ and compared against the maximum difference Δmax. When the difference Δ is less than the maximum difference Δmax, the rotating laser meets the specified accuracy. In the event that the difference Δ is greater than the maximum difference Δmax or equal to the maximum difference Δmax, an adjustment of the rotating laser is necessary.
Embodiments of the invention are described below with reference to the accompanying drawing. The intention is not necessarily to depict the embodiments to scale; rather, the drawing, where useful for the sake of explanation, is drawn in a schematic and/or slightly distorted form. It should thereby be taken into account that diverse modifications and changes pertaining to the form and detail of a design may be undertaken without departing from the general idea of the invention. The general idea of the invention is not restricted to the exact form or detail of the preferred design shown and described below or restricted to a subject matter that would be restricted in comparison to the subject matter claimed in the claims. In regard to provided measurement ranges, values lying within the mentioned limits shall be disclosed as limit values and be arbitrarily usable and claimable. For the sake of simplicity, the same reference numbers are used below for identical or similar parts, or parts with identical or similar functions.